1. Field of the Invention
The present invention relates to a pneumatic grinder with an improved air intake control apparatus, and more particularly to a technology of controlling an air intake by turning a press board by fingers.
2. Description of the Related Art
Referring to FIG. 6 for a conventional pneumatic grinder, and an air intake control apparatus 41 of this kind of pneumatic grinders is installed at a position of a handle 42 proximate to a grinding head 43, such that when a user holds the handle 42 for a grinding job, the user presses onto a press board 411 of the intake control apparatus 41 by the center of a palm, and an end of the press board 411 is pivotally connected to a top surface of the handle 42 and at a position proximate to the grinding head 43, and another end of the press board 411 is lifted towards a rear end of the handle 42, wherein the bottom of a middle section of the press board 411 presses downward onto a rod 412, so that when the user presses the press board 411 by a palm, the rod 412 is pressed downward by the press board 411 at the same time to drive a valve rod 413 of the air intake control apparatus 41 to circulate air, so as to drive a pneumatic motor 44 at the position of the grinding head 43.
However, the conventional way of holding the grinder is very inconvenient and not favorable for a user's grip, because the user's wrist and lower arm are driven to move while the user's palm is pressing onto the press board 411, and thus the prior art takes much efforts and causes the grinding head 43 to shake easily. As a result, errors may be produced in the grinding job. Pressing the press board 411 by a palm also causes an inconvenient grip, so that when the pneumatic motor is operated and vibrated, the grip may be loosened easily.
Therefore, the technique of designing the press board of the air intake control apparatus 41 at the top of the handle 42 as described above requires feasible solutions and improvements.
In other words, if users can operate the tool by fingers, then the requirement for the controlling the operation can be met, since fingers are the most skillful part of a human hand.
If the original design of using a palm to press onto the press board of the aforementioned conventional grinder is replaced by a design of using fingers for the operation of the grinder, the shortcomings of the conventional grinder can be overcome. To let the press board be pressed and operated directly by fingers when a user holds the handle by a hand, it is necessary to redesign and install the press board at the bottom of the handle, but such arrangement will change the positions of many related components of the air intake control apparatus. It is noteworthy to point out that the space at the bottom of the handle of the grinder and proximate to the grinding head is narrower than the space at the top of the handle and proximate to the grinding head, so that when the press board is redesigned and installed at the bottom of the handle and proximate to the grinding head, the press board will move much further to the rear side of the handle than its original position at the top of the handle. Since the air intake control apparatus comes with a speed adjusting knob, therefore it is necessary to redesign a rotating portion of the speed adjusting knob at the top of the handle when the press board is designed at the bottom of the handle. Furthermore, the original way of using an end of the press board for a pivotal connection and pressing makes the position of the speed adjusting knob closer to the middle section of the handle, such that when a user holds the handle by a hand, the user will feel a sudden obstacle, and find it uneasy or uncomfortable to hold the handle.
Although the press board of the conventional grinder can be redesigned at the bottom of the handle, such that users can press and operate the press board directly by fingers, yet the grinder with an adjusted position of the press board still has an existing problem that users find it uneasy to hold the handle due to the position of the speed adjusting knob.